FORMING APPARATUS AND METHOD FOR FORMING A CONTINUOUS TUBULAR ROD

Abstract

The forming apparatus comprises a feed path for continuously feeding a continuous tow material along a transport direction, a forming device connected to a downstream end of the feed path and adapted to form the continuous tow material into a continuous tubular rod. The forming device comprises a tubular element adapted to allow the continuous tow material to pass through the tubular element to form the continuous tubular rod and a steam generator adapted to generate overheated steam. The steam generator is in fluid connection with the tubular element to provide overheated steam to the continuous tow material. The forming device further comprises several fluid conduits to provide overheated steam from the steam generator to several injection sites arranged along a length of the tubular element, wherein at least one fluid conduit of the several fluid conduits comprises a temperature control unit including a temperature sensor and a temperature influencer.

Claims

1-15. (canceled)

16. A forming apparatus comprising: a feed path for continuously feeding a continuous tow material along a transport direction; a forming device connected to a downstream end of the feed path and adapted to form the continuous tow material into a continuous tubular rod, the forming device comprising: a tubular element adapted to allow the continuous tow material to pass through the tubular element to form the continuous tubular rod; a steam generator adapted to generate overheated steam, the steam generator being in fluid connection with the tubular element to provide overheated steam to the continuous tow material, wherein the forming device further comprises several fluid conduits to provide overheated steam from the steam generator to several injection sites arranged along a length of the tubular element, and wherein more than one fluid conduit of the several fluid conduits comprises a temperature control unit including a temperature sensor and a temperature influencer.

17. The forming apparatus according to claim 16, wherein one of the more than one temperature control unit is arranged in an end section of a fluid conduit at the injection site.

18. The forming apparatus according to claim 16, wherein an injection end of the at least one fluid conduit, which fluid conduit comprises the temperature control unit comprises a nozzle.

19. The forming apparatus according to claim 18, wherein the temperature sensor is arranged in the nozzle.

20. The forming apparatus according to claim 16, wherein the temperature influencer is a heating device, preferably a heating and cooling device.

21. The forming apparatus according to claim 16, wherein each fluid conduit of the several fluid conduits, comprises a temperature control unit.

22. The forming apparatus according to claim 16, wherein at least one fluid conduit of the several fluid conduits comprises a pressure control unit comprising a pressure sensor and a pressure influencer.

23. The forming apparatus according to claim 22, wherein the pressure influencer is a pressure regulator capable to diminish a pressure, preferably to diminish and enhance a pressure, in the fluid conduit.

24. The forming apparatus according to claim 16, wherein the tubular element comprises a plurality of tubular element segments, wherein each tubular element segment of the plurality of tubular element segments comprises an injection site.

25. The forming apparatus according to claim 16, wherein the tubular element comprises a mandrel for forming a continuous hollow tubular rod from the continuous tow material.

26. A manufacturing line for manufacturing a continuous tubular rod, the manufacturing line comprising a forming apparatus according to claim 16 and comprising a plasticiser application device arranged upstream of the forming apparatus for applying plasticiser to the continuous tow material.

27. A method for forming a continuous tubular rod from a continuous tow material, the method comprising: providing a continuous tow material; forming the continuous tow material to a continuous tubular rod; heating the continuous tow material during forming by providing overheated steam from a steam generator via a steam distribution system to the continuous tubular rod, thereby measuring the temperature of the overheated steam in the steam distribution system at several injection sites of the overheated steam to the continuous tubular rod along a forming path of the continuous tow material, and providing a temperature influencer in the steam distribution system downstream of the steam generator, the temperature influencer capable of changing a temperature of the overheated steam delivered from the steam generator to the continuous tow material during forming.

28. The method according to claim 27, comprising heating or cooling the overheated steam delivered from the steam generator before delivering the overheated steam to the continuous tow material.

29. The method according to claim 27, comprising measuring the pressure of the overheated steam at least one of the injection sites and providing a pressure influencer in the distribution system, the pressure influencer being capable of changing the pressure, preferably diminish the pressure, of the overheated steam delivered to the continuous tow material.

Description

[0058] The invention is further described with regard to embodiments, which are illustrated by means of the following drawings, wherein:

[0059] FIG. 1 is a schematic view of a forming apparatus with temperature control unit;

[0060] FIG. 2 shows a perspective view of a forming apparatus comprising several tubular element segments;

[0061] FIG. 3 shows a forming apparatus with formed inner tube within the tubular element segments;

[0062] FIG. 4 is a schematic view of a forming apparatus with temperature and pressure control unit;

[0063] FIG. 5 schematically shows a continuous rod manufacturing line;

[0064] FIG. 6 is a schematic illustration of a forming apparatus for example used in the manufacturing line shown in FIG. 5.

[0065] In FIG. 1 the continuous material 1, for example tow material impregnated with a plasticizer, for example triacetin, is guided along the transport direction 100. The continuous material is guided through a tubular element (not shown) and thereby treated with overheated steam.

[0066] The overheated steam is generated in a steam generator 2 and guided via steam distribution system to the tow material 1. The overheated steam is guided to the tubular element where the tow material is passing through and thereby formed into a rod. The flow direction of the overheated steam is shown by arrow 200.

[0067] Typically, the steam distribution system comprises a manifold distributing the overheated steam from the steam generator 2 into a plurality of individual pipes 20. In FIG. 1 a single end portion of a steam distribution system is shown as fluid conduit in the form of one pipe 20. The pipe 20 ends in a nozzle 21 focussing the overheated steam to the tow material 1. This end portion of the steam distribution system is provided with a temperature control unit 3. The temperature control unit 3 comprises a heating element 30, for example a resistive heating element, surrounding the pipe 20. The temperature control unit 3 also comprises a temperature sensor 31 arranged in the nozzle 21. The temperature control unit 3 may also comprise a data control system and a power system for retrieving data from the temperature sensor 31 and from the heating element 30 and for providing the heating element 30 with heating power when needed to heat the overheated steam to a higher temperature and also to a higher pressure. The pipe 20 is made of a material to resist the heat of the overheated steam as well as the heat provided by the heating element 30.

[0068] While the steam distribution system and temperature control is shown in FIG. 1 by way of one pipe 20 provided with a temperature control system 3, the steam distribution system preferably comprises several individual pipes that may be provided with their own individually controlled temperature control unit.

[0069] Data control system and power system for the temperature control unit 3 may also be integrated in a main control system provided for control of the forming apparatus and possibly also further devices used in the rod manufacturing process.

[0070] In some embodiments, the heating element 30 may be a cooling element or a combined heating and cooling element. By this, the overheated steam may be cooled, or may be heated or cooled depending on the temperature of the overheated steam delivered from the steam generator 2 and the temperature of the overheated steam needed for treating the continuous material.

[0071] In FIG. 2, the forming device comprises a tubular element 41 realized by a plurality of separated elements, five tubular element segments 410, disposed in series along the feeding direction of the continuous material.

[0072] At least the pipe 20 leading to the first of the separated element segments 410 (most upstream arranged segment) is provided with a temperature control unit 3 (not shown). Preferably the pipes leading to the first and second of the separated element segments 410 are provided with a temperature control unit 3. Thus, at least the two most upstream arranged pipes 20 are made of a material resistant to the heat provided by the heating element 30.

[0073] Preferably, a last of the separated element segments 410 (most downstream arranged segment) is used for cooling the continuous rod, for example by guiding pressurized air to the interior of the element segment 410. A pipe 20 leading the pressurized cooling air to the last element segment 410 does not require the heat resistance of the pipes with the heating element and may thus be made of a less heat resistant material than the pipes provided with a heating element.

[0074] In FIG. 3, the last one of the tubular element segments 410 when seen in transport direction of the tow material, is shown to comprise a formed inner tube 44 located within the tubular element segment 410. The tow passing through the tubular element segment 410 passes along the inner surface of the formed inner tube 44. The formed inner tube thus imparts its form onto the outside of the tow during the forming. Preferably, the formed inner tube comprises a substantially circular cross section. Particularly advantageously, the formed inner tube 44 creates a number of flutes along the periphery of the formed tow, for example for air to pass along the flutes. Preferably all tubular element segments 410 of the tubular element 41 comprise an inner tube 44. Most preferably, upstream arranged element segments 410 that are provided with overheated steam for heating the tow material are provided with an inner tube 44.

[0075] FIG. 4 shows in a simplified manner another example of a forming apparatus. The same or similar reference signs are used for the same or similar features as in FIG. 1.

[0076] The forming apparatus comprises a steam generator 2 and a steam distribution system wherein only one pipe 20 of the distribution system is shown. The pipe 20 is provided with a temperature control unit 3 provided in a pipe end section of the steam distribution system.

[0077] The pipe 20 is additionally provided with a pressure control unit 5. The pressure control unit 5 comprises a pressure sensor 51 for measuring the pressure of the overheated steam. The pressure sensor is arranged upstream of the heating element 30. The pressure control unit 5 also comprises a pressure influencer 50,52. The pressure influencer in the embodiment shown consists of two propellers 50 and a pressure regulator 52, for example a valve.

[0078] One of the propellers 50 is arranged in the pipe upstream of the pressure sensor 51. The second propeller 50 is arranged downstream of the heating element 30 but upstream of the pressure regulator 52 when seen in flow direction 200 of the overheated steam. Preferably, a velocity sensor is arranged at the position of the second propeller for measuring the velocity of the overheated steam. As the pressure regulator is arranged immediately upstream of the nozzle 21, where the overheated steam is introduced into the tubular element 41, with the pressure regulator, the pressure of the overheated steam to be applied to the tow material may be controlled and adjusted very precisely. In particular, any pressure increase possibly occurring due to a heating of the overheated steam, may be equalised by the pressure regulator 52.

[0079] The various sensors and actuators may measure and act on temperature, velocity and pressure of the overheated steam.

[0080] As already mentioned for the embodiment of the forming apparatus of FIG. 1, also the forming apparatus shown in FIG. 4 may comprise several pipes and more than one pipe may be provided with their own individually controlled temperature control unit 3 and with their own individually controlled pressure control unit 5.

[0081] Temperature and pressure control units 3,5 allow to adjust the temperature, pressure and velocity of the overheated steam after the overheated steam has left the steam generator 2 and basically at the exit of the one or several pipes 20. The serial provision of injection nozzles and temperature and pressure control units 3,5 allows to get, preferably independently, temperature and pressure profiles successively at different application points in the rod forming process.

[0082] This also applies if one or more downstream arranged pipes are used for cooling, for example by application of pressurized air. By measuring the temperature and pressure of the pressurized air applied to the tow material or to the already formed but not entirely stabilized rod, a controlled hardening and form stabilization may be achieved. This advantageously applies if the temperature and pressure is controlled sequentially in the cooling process.

[0083] FIG. 5 shows a manufacturing line for producing continuous rods or continuous rod components, preferably for aerosol-generating articles. Preferably, hollow rods of cellulose acetate are manufactured that are cut into segments. These segments may be used in heat-not-burn aerosol-generating articles.

[0084] The manufacturing line comprises a transport device 10 to transport continuous material, for example cellulose acetate tow material, along a transport or feeding direction 100.

[0085] Along the manufacturing line a preparation unit 7 is arranged. The tow material is fed to the preparation unit 7 by the transport device 10. The preparation unit 7 is adapted to form a continuous stream of tow material, moistened with a hardening fluid or plasticizer, such as for example triacetin. In the embodiment of FIG. 5, the plasticizer unit is part of the preparation unit 7. Plasticizer units are known in the art. The plasticizer unit may also be located upstream of the preparation unit 7. Downstream of the preparation unit 7, the manufacturing line includes a forming apparatus 4, arranged in series to the preparation unit 7. The forming apparatus 4 is adapted to receive the flow of tow material and to cause hardening of the material to transform the tow material into a continuous axially rigid rod.

[0086] Advantageously, the manufacturing line further includes a wrapping unit 8, to wrap the rod in a wrapping paper. Further, the manufacturing line may comprise a cutting unit 9, preferably a rotating cutting head of known type. The cutting unit 9 is arranged downstream of the forming apparatus 4 and wrapping unit 9 and adapted to cut the rod into rod segments. A desired length of the segments in which the rod is cut is for example obtained with the assistance of an appropriate measuring device (not shown).

[0087] Suitable wrapping unit 8, transport device 10 and cutting unit 9 are known in the art and not further described.

[0088] The manufacturing line includes a main control system 500 adapted to receive and send signals from and to the forming apparatus 4. With the main control system 500, for example the heating or non-heating of a temperature control unit or, if present, a pressure regulator may be controlled. Preferably, the main control system 500 also controls further units of the manufacturing line, for example the preparation unit 7 and the transport device 10. Also the wrapping unit 8 and cutting unit 9 may be controlled by the main control system 500.

[0089] The forming apparatus 4 is shown in an enlarged view in FIG. 6. The forming apparatus 4 comprises a tubular element 41 adapted to receive the tow material saturated with hardening material. The transport direction of the transport device 10, as well as the feeding direction of the tow material into the tubular element 41 of the forming apparatus 4 is depicted with arrow 100.

[0090] The tubular element 41 is adapted to shape the tow material to transform it into a generally cylindrical rod, for example into a full rod or into a hollow rod, and to advance the rod in the feed direction 100 to the further components of the manufacturing line.

[0091] The tubular element 41 defines a hole 45 through which the tow material can pass. Preferably, the hole 45 comprises an inner surface 451. The inner surface 451 compresses the tow material to form a substantially cylindrical rod-like shaped continuous tow of material. The inner surface 451 may, for example be an inner surface of a formed inner tube 44 as described in FIG. 3.

[0092] The tubular element 41 may comprise a mandrel arranged inside the tubular element. The continuous tow material is then guided around and along the mandrel and within the inner surface 451, thus forming a hollow tube of tow material.

[0093] The forming apparatus 4 further comprises a steam generator 2 in fluid connection with two circular nozzles 21 to inject pressurized overheated steam into the interior of the tubular element 41. The overheated steam hardens the plasticizer present in the tow material and transforms it into a substantially rigid rod.

[0094] In the embodiment of FIG. 6, the tubular element 41 is a single continuous tubular element comprising two injection sites for the overheated pressurized steam to act on the continuous material. Preferably, more than two, for example three to five nozzles 21 are present for injecting overheated steam or also pressurized air at three to five injections sites arranged along the tubular element 41.